Power light on but screen stays black

The first thing we need to do is identify your machine exactly. Look on the bottom of the stand and find the EMC number. Is it an intel processor? These machine have slight differences and entry into them is different on the G5 models and the Intel models. Do you get a chime when turning it on?

"Hello, I just went through this (today) with my 20"" iMac Core 2 Duo after replacing the RAM. If you've replaced the RAM or taken them out for some reason...

What worked for me was to unplug, take the RAM out re-insert, hold power button down for 5 sec. plug back in and was good to go! Good luck!"

There is no chime when the machine is turned on and the Model number is A1195, Yes it is an intel processor

"Wow, no chime, that's veeery bad! THat means the motherboard hadn't passed the self-check.

Have you done anything particular before the ""death""? That's a problem that can't come out from nothing.

If you want you can try an EPROM reset, by doing what is written here --> http://support.apple.com/kb/HT1379

Try even disconnecting the mac from power supply and keeping the power button held for some seconds (10-15)"

"all those answers are rubbish,

this answer from elva carri on ifixit is much better,

I had the same issue. Tried everything here bar the teepee suggestion which i was intrigued by but went for a free diagnosis at a repairs shop before trying that one.

In my case it was a broken ram slot so it works with one piece of ram removed.

Regarding the teepee method the guys in this repairs shop have a machine that does the same thing. They call it floating it and i think were impressed at your idea of how you could do this yourself, thought it sounds like in my case it wouldn't have fixed it.

best of luck"